When conducting research into the effects of seismic activity on structures such as bridges and buildings, it is important to take fast measurements simultaneously. In addition the vibration can cause signal aliasing to occur on measurement readings. So obtaining an accurate reading on these high frequency signals requires the use of anti-aliasing filters or digital filters.

Digital filters allow all the signals including noise into your measurement system, after which they are digitally filtered out.

Anti-aliasing filters use analog circuitry to remove the unwanted noise before it gets into the measurement system, thereby enabling a much better analysis of the signal you want to measure.

An ideal system for this type of application uses the iDSC 1816, which is an eight channel simultaneous sampling analog input PCI board, which has an on-board processor and real-time operating system. It comes with programmable anti-aliasing filters which can be set individually for each channel, and can transfer samples to the PC at up to 153kS/s per channel.

To acquire readings simultaneously from 32 strain gauge sensors, four iDCS 1816 can be installed in a PC and synchronised. The SCS32 signal conditioning system provides excitation for 32 bridge networks with programmable gain. This is connected to the four iDSC 1816 to complete the 32 channel system.